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  1. hevans1944

    Help to make an old analogue factory 500 amp meter become a sound meter

    Well, It is obvious to those of us "skilled in the art," but the OP in post #3 admitted having no such skill, so I thought I would mention it. I would like to know what he meant by the statement "I removed some of the coil to increase the sensitivity of the needle which worked." What exactly did...
  2. hevans1944

    Help to make an old analogue factory 500 amp meter become a sound meter

    Since it IS a moving iron meter, instead of a moving coil, removing turns of wire from the coil should not increase the "sensitivity" but instead decrease the inductance of the coil, as well as decreasing the magnetic field produced when current flows through the coil, and hence the reactive...
  3. hevans1944

    Capacitor in a DC circuit

    Capacitors pass AC signals while blocking DC. Removing the capacitor would block both signals. Thus a capacitor is useful when you don't want to disturb the DC biasing conditions on either side of the capacitor and simply pass an AC signal from stage to stage... capacitance-coupled amplifier...
  4. hevans1944

    IP video camera.

    We could probably offer more specific advice if you would tell us the Manufacturer and the Model of the camera you are using. Or is it a "no name" clone of who knows what?
  5. hevans1944

    Load Capacitance for an Oscillator

    Didn't see any reference to reactance. The maximum load with the clipped sine version is 10 kΩ resistive in parallel with 10 pF capacitance. More resistance, less capacitance in the load in preferable. The HCMOS version is expected to drive the very high impedance of an HCMOS gate with a maximum...
  6. hevans1944

    Identify this component

    The only thing I see worth salvaging is the crystal oscillator, located in the oblong silver can at the lower left corner of your photo... unless you need a few dozen or so SMD resistors and capacitors of unknown (but measurable) value. The proprietary microcontroller under the epoxy blob isn't...
  7. hevans1944

    Load Capacitance for an Oscillator

    It is designed to drive HCMOS, so the spec is probably the maximum capacitance allowable for the load to guarantee the rise time spec. The oscillator output would normally be buffered by a gate or HCMOS driver to distribute the clock. Don't use long PCB traces over a ground plane to connect the...
  8. hevans1944

    Did I get shocked by my TV power supply?

    This may just be your sub-conscious telling you to quit messin' around with electronics...
  9. hevans1944

    Homemade 555 Tachometer

    Playing is what we do here! All who have responded with advice and links are quite active here and enjoy welcoming and helping others to become more acquainted with electronics. Where you go from here is entirely up to you, but this is a good place to find help when you need it. The circuit you...
  10. hevans1944

    Induction cooker

    Try reading the information at this Wikipedia link. Most industrial induction coil heaters will heat most anything conductive, but for efficiency a ferromagnetic susceptor is used to take advantage of the losses caused by magnetic hysteresis, a stronger mechanism than simple Joule heating...
  11. hevans1944

    How does a GPS receiver/transmitter (transceiver) work on a circuit board?

    Everything you need is already integrated into a smartphone. All you need to do is write an app for the phone, then duct tape (or otherwise attach) the phone to the ski pole handle. Problems I see with this approach are (1) limited or no range with cellphone buried in snow; (2) limited battery...
  12. hevans1944

    Anyone have any oscilloscope recommendations?

    I spent a year in Phoenixville, PA while Dad was recovering from tuberculosis at nearby Valley Forge Army Medical center. After he recovered, his last duty assignment was to an Air Force base near Smyrna, TN. I really liked Pennsylvania when I was there at the end of the 1950s. Had a nice Sunday...
  13. hevans1944

    Designing a schedule enabled music player with BT connectivity

    You need to integrate an SD memory card to store the music clips, plus a Bluetooth interface to download commands and data. The RPi, being a "real" computer with a Linux OS offloads most of the housekeeping details, which is why I recommended it. It IS a power hog, comparatively speaking, and...
  14. hevans1944

    SAFE Regulated Power Supply

    Looks like it puts out 65.8 A at 12 V and 800 watts dissipation. That works out to 789,6 watts. Is that good enough for you?
  15. hevans1944

    Need relay that operates with 3.8 VDC input.

    If you can find 5 V somewhere (maybe the circuit from which your 3.8 V DC is derived) you can use it to power the relay through a transistor switch controlled by your 3.8 V DC. If the raw DC supply voltage is much higher than 3.8 V DC, you can use a relay with a higher coil voltage, still...
  16. hevans1944

    Anyone have any oscilloscope recommendations?

    Yes, it sounds like we trod similar paths. I found high school very boring... except for my junior year at a school in Smyrna, TN, where I had an "old school" chemistry teacher. She believed in a "hands-on, taste, sniff, and smell" kind of chemistry that is verboten today. She encouraged me to...
  17. hevans1944

    Designing a schedule enabled music player with BT connectivity

    Sounds like a job for a Raspberry Pi microcomputer. Just add some software.
  18. hevans1944

    How To Prevent Short Circuit With A Simple Wire From One Outlet Prong To The Other

    Both your SCENARIO A and SCENARIO B show "light weight copper wire" connecting to the convenience outlet. There are devices that show a small resistance that abruptly increases with increasing current: polyfuses. But it would help if we knew what you want to DO with that "light weight copper...
  19. hevans1944

    Physics Project Timer

    It seems to me that you would want to have a sensor on the vehicle that detects the presence of the wall and responds accordingly.
  20. hevans1944

    SAFE Regulated Power Supply

    Read the label on the power supply. There are four outputs, each with different current ratings. And the current ratings depend on the power rating from 800 watts to 1000 watts.
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